diff options
| author | Daniel Scheller <d.scheller@gmx.net> | 2017-08-23 19:09:59 +0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2017-08-27 13:36:01 +0300 |
| commit | 1502efd2d5960c11593c5f002278cdc1e14c4520 (patch) | |
| tree | e89225904402f1db8ff54846dad4490938238f46 /drivers/media | |
| parent | 6b852620fa75d3137929538b4a9aec2f953ff03c (diff) | |
| download | linux-1502efd2d5960c11593c5f002278cdc1e14c4520.tar.xz | |
media: ddbridge: fix teardown/deregistration order in ddb_input_detach()
Brought to attention by Matthias Schwarzott <zzam@gentoo.org> by fixing
possible use-after-free faults in some demod drivers:
In ddb_input_detach(), the i2c_client is unregistered and removed before
dvb frontends are unregistered and detached. While no use-after-free issue
was observed so far, there is another issue with this:
dvb->attached keeps track of the state of the input/output registration,
and the i2c_client unregistration takes place only if everything was
successful (dvb->attached == 0x31). If for some reason an error occurred
during the frontend setup, that value stays at 0x20. In the following
error handling and cleanup, ddb_input_detach() will skip down to that
state, leaving the i2c_client registered, causing refcount issues.
Fix this by moving the i2c_client deregistration down to case 0x20.
Cc: Matthias Schwarzott <zzam@gentoo.org>
Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'drivers/media')
| -rw-r--r-- | drivers/media/pci/ddbridge/ddbridge-core.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/media/pci/ddbridge/ddbridge-core.c b/drivers/media/pci/ddbridge/ddbridge-core.c index 2464bde1c432..281b6739b0c1 100644 --- a/drivers/media/pci/ddbridge/ddbridge-core.c +++ b/drivers/media/pci/ddbridge/ddbridge-core.c @@ -1255,11 +1255,6 @@ static void dvb_input_detach(struct ddb_input *input) switch (dvb->attached) { case 0x31: - client = dvb->i2c_client[0]; - if (client) { - module_put(client->dev.driver->owner); - i2c_unregister_device(client); - } if (dvb->fe2) dvb_unregister_frontend(dvb->fe2); if (dvb->fe) @@ -1273,6 +1268,12 @@ static void dvb_input_detach(struct ddb_input *input) dvb->fe = dvb->fe2 = NULL; /* fallthrough */ case 0x20: + client = dvb->i2c_client[0]; + if (client) { + module_put(client->dev.driver->owner); + i2c_unregister_device(client); + } + dvb_net_release(&dvb->dvbnet); /* fallthrough */ case 0x12: |